Contents
Overview 1
Introduction to System Services 2
Logical Design of System Services 6
Physical Design of System Services 10
Market Purchasing 19
Best Practices 22
Lab 11: System Services 23
Review 27

Module 11: System
Services

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General Manager: Robert Stewart

Module 11: System Services iii Instructor Notes
This module provides students with an introduction to system services. This
module focuses on the system services layer. The system services layer works
with parts of the application that provide system service or system
infrastructure functionality. Typically, any layer within the architecture can use
the system services layer. Examples include page caching, auditing, and
searching.
After completing this module, students will be able to:
!
Describe the logical design of a system services layer.
!
Describe the functionality of authentication.
!
Describe the functionality of a search.
!
Describe the functionality of an audit.
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Describe application instrumentation.
!
Describe the physical design of a system services layer and how to apply the
technologies presented in this module.

Materials and Preparation
This section provides the materials and preparation tasks that you need to teach

Use the following strategy to present this module:
!
Introduction to System Services
The purpose of this section is to introduce students to the system services
layer. The system services layer works with parts of the application that
provide system service or system infrastructure functionality. Explain the
business problem by using the example of authentication, and then use the
same example to illustrate the business requirements in the next topic.
!
Logical Design of System Services
The purpose of this section is to introduce the Authentication design pattern
that was created as a part of this course.
Discuss the design pattern in detail. Solicit comments from the students
about the value they think this pattern adds to a logical design. For a
discussion point, ask students what other system services might be good
candidates as design patterns.
!
Physical Design of System Services
The purpose of this section is to identify the considerations in the physical
design of system services. These considerations include crossing layer
boundaries, auditing, authentication, and application instrumentation.
In the topic “Application Instrumentation,” focus on the use of Microsoft

Windows
®
Management Instrumentation (WMI). Also mention that WMI is
the Microsoft implementation of Web-Based Enterprise Management
(WBEM).
WBEM is an industry initiative undertaken by the Distributed Management
Task Force (DMTF) to provide enterprise system managers with a standard

Lab 11: System Services
The purpose of Lab 11 is to teach students how to design system services.
Students might present answers that differ from those included in the lab.
This is acceptable as long as the student answers are justified and are well
thought out. Discuss with students their answers to Lab 11.

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Module 11: System Services 1 #
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Overview
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Introduction to System Services
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Logical Design of System Services
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Physical Design of System Services
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Market Purchasing
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Best PracticesThis module is about the system services layer. The system services layer
works with parts of the application that provide system service or system

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Introduction to System Services
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The Business Problem
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Business RequirementsThe system services layer interacts with other architecture layers to provide
generic services to an enterprise solution. The other architecture layers include
the user services layer, the facade layer, the business logic layer, and the data
access layer (DAL).
In this section, the system services layer will be placed in the proper context of
the business problem. This will be followed by a presentation on the logical
design of a system services layer that will focus on behavioral design patterns.
Finally, there will be a brief presentation on the physical design of a system
services layer.
Topic Objective
To provide an overview of
the section topics and
objectives.
Lead-in
In this section, you will learn
what makes up a system
services layer.
Module 11: System Services 3
Topic Objective
To provide background
about the business problem.
Lead-in
In this section, you will learn
about the business problem
facing application designers
that leads to the need for a
system services layer.
4 Module 11: System Services Business Requirements
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Crossing Layer Boundaries
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Authentication
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Auditing
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Application Instrumentation
Application Community
Windows 2000
UsersThere are four business requirements of system services: the need to cross layer
boundaries, the need for authentication, the need for auditing, and the need for
application instrumentation in implementing a solution.
Crossing Layer Boundaries

requirements for
implementing system
services.
Module 11: System Services 5 Application Instrumentation
The need for application instrumentation in implementing system services
arises out of the need for the solution to provide a mechanism for managing its
internal state and behavior variables.
In a subsequent section you will learn about the important physical design
features of crossing layer boundaries, authentication, auditing, and application
instrumentation.
6 Module 11: System Services #
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# Logical Design of System Services
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The Audit System Service
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The Authentication Design PatternIn this section, you will learn about designing auditing as a system service. You
will also learn about designing authentication as a system service, and about a
new behavioral design pattern for implementing authentication.
If you are concerned about the need for creating new patterns, you should refer
to Chapter 1, “The Top Ten Misconceptions,” in Pattern Hatching, Design

receivers need to act on. Auditing involves multiple clients posting log entries
to a receiver that is the auditing service itself. By using a durable queue,
processing of log entries can be queued until a batch process retrieves them.
Batching log entries in this manner improves system performance.

Topic Objective
To provide an overview of
the audit system service.
Lead-in
In this section, you will learn
about the audit system
service.